基于增强声子散射在单个晶界附近热导率抑制的直接可视化
摘要
理解晶格缺陷对纳米尺度热输运的影响对于从热管理到能量转换的多种应用至关重要。晶界（GBs）是多晶材料中普遍存在的缺陷，会散射声子并降低热导率。历史上，其对热传导的影响是通过空间平均测量间接研究的，几乎无法提供关于单个晶界附近声子输运的信息。在此，我们结合使用空间分辨时域热反射率（TDTR）测量与电子背散射衍射（EBSD），对硼掺杂多晶金刚石中单个晶界附近数 \mu m 范围内的热导率进行了局域测量。我们观察到晶界附近热输运被强烈抑制，热导率从大晶粒中心的约 1000 W/m-K 降至晶界紧邻区域的约 400 W/m-K。此外，我们表明该热导率的降低在距晶界约 10 \mu m 处仍可测得。我们提出了一个理论模型，捕捉了由于无序晶界处强漫散射声子所导致的声子平均自由程的局域减小。我们的结果为理解纳米材料中声子-缺陷相互作用提供了新框架，对高导热多晶材料作为电子热管理中散热器的使用具有启示意义。
引用
@article{arxiv.1804.04163,
title = {Direct Visualization of Thermal Conductivity Suppression Due to Enhanced Phonon Scattering Near Individual Grain Boundaries},
author = {Aditya Sood and Ramez Cheaito and Tingyu Bai and Heungdong Kwon and Yekan Wang and Chao Li and Luke Yates and Thomas Bougher and Samuel Graham and Mehdi Asheghi and Mark Goorsky and Kenneth E. Goodson},
journal= {arXiv preprint arXiv:1804.04163},
year = {2018}
}
备注
This document is the unedited Author's version of a submitted work that was subsequently accepted for publication in Nano Letters, copyright American Chemical Society after peer review. To access the final edited and published work see this URL: https://pubs.acs.org/doi/10.1021/acs.nanolett.8b00534. Version 2: Updates Supplementary Figs S1 and S3. The journal published version is correct